Psych Exam 1 Study Guide
Chapter 1: Foundations of Psychology
• Wilhelm Wundt
◦ Background: A German professor who launched a campaign to make psychology an independent scientific discipline, rather than a sub-field of philosophy or physiology.
◦ Founding of Psychology: Established the first formal laboratory for research in psychology in 1879 at the University of Leipzig, marking psychology's "date of birth". In 1881, he also established the first journal for psychological research. He is widely regarded as the founder of psychology.
◦ Conception of Psychology: Wundt proposed that the new psychology should be a science, modeled after fields like physics and chemistry.
◦ Subject Matter: According to Wundt, the primary subject matter of this new science was consciousness—the awareness of immediate experience. Thus, he defined psychology as the scientific study of conscious experience.
• Edward Titchener/Structuralism/Introspection
◦ Leadership: Structuralism emerged under the leadership of Edward Titchener, an Englishman who studied in Wundt's lab and later taught at Cornell University.
◦ Structuralism: This school of thought was based on the idea that the task of psychology is to analyze consciousness into its basic elements and investigate how these elements are related. Structuralists aimed to identify the fundamental components of conscious experience, such as sensations, feelings, and images, similar to how physicists studied basic particles of matter.
◦ Introspection: The primary method used by structuralists to examine the contents of consciousness was introspection, which involves the careful, systematic self-observation of one's own conscious experience. This method required rigorous training for subjects to become objective and aware of their experiences, typically involving exposure to stimuli and then analyzing and describing the quality, intensity, and clarity of what they experienced.
• William James/Functionalism/Stream of Consciousness
◦ Influence: William James, a brilliant American scholar, heavily influenced the development of functionalism.
◦ Functionalism: This school of thought was based on the belief that psychology should investigate the function or purpose of consciousness, rather than its structure. James argued that structuralism's approach missed the true nature of conscious experience by trying to break it into static elements.
◦ Stream of Consciousness: James conceptualized consciousness as a continuous flow of thoughts, which he called the "stream of consciousness". This metaphorical description was a revolutionary insight at the time.
◦ Focus: Functionalists were interested in how people adapt their behavior to the demands of the real world, exploring topics such as mental testing, patterns of child development, the effectiveness of educational practices, and behavioral differences between sexes.
◦ Historical Impact: Functionalism is generally considered by historians to have "won" the first great intellectual battles in psychology and fostered the development of behaviorism and applied psychology.
• James Watson/Behaviorism
◦ Advocacy: John B. Watson became a leading advocate for behaviorism in the early 1900s.
◦ Core Premise: Behaviorism is a theoretical orientation based on the premise that scientific psychology should study only observable behavior. Watson proposed that psychologists should abandon the study of consciousness entirely and focus exclusively on directly observable behaviors.
◦ Rationale: Watson argued that mental processes were not suitable for scientific study because they are private events and cannot be objectively observed or verified, which is crucial for the scientific method.
◦ Definition of Behavior: Behavior refers to any overt (observable) response or activity by an organism.
◦ Nature vs. Nurture Stance: Watson took an extreme position on the nature versus nurture debate, maintaining that behavior is governed entirely by the environment, discounting the importance of heredity. He famously claimed he could train any healthy infant to become any type of specialist, regardless of their talents or ancestry.
◦ Impact: Behaviorism contributed to the rise of animal research in psychology, as the study of consciousness was no longer required, and animals offered greater experimental control.
• Sigmund Freud/Psychoanalysis, Unconscious
◦ Influence: Sigmund Freud, an Austrian physician, developed theories that made him one of the most influential—and controversial—intellectual figures of the 20th century.
◦ Psychoanalysis: Freud's approach to psychology, psychoanalysis, grew out of his efforts to treat mental disorders like irrational fears, obsessions, and anxieties.
◦ The Unconscious: A central concept in Freud's theory is the unconscious, which he proposed contains thoughts, memories, and desires that are well below the surface of conscious awareness but nonetheless exert great influence on behavior. He observed phenomena like slips of the tongue and dreams as revealing unconscious feelings.
◦ Psychoanalytic Theory: This theory attempts to explain personality, motivation, and mental disorders by focusing on unconscious determinants of behavior.
◦ Controversy: Freud's ideas were controversial because they suggested that people are not masters of their own minds and that behavior is greatly influenced by how individuals cope with their sexual urges, a topic that was scandalous at the time. Despite initial debate, psychoanalytic concepts have become influential and filtered into mainstream psychology.
• B. F. Skinner
◦ Behaviorism's Flourishing: In the 1950s, Harvard psychologist B. F. Skinner dramatically advanced behaviorism.
◦ View on Internal Events: Skinner did not deny the existence of internal mental events but insisted that they could not be studied scientifically and were unnecessary for explaining behavior.
◦ Environmental Influence: Like Watson, Skinner emphasized the role of environmental factors in shaping behavior.
◦ Fundamental Principle: Skinner documented the principle that organisms tend to repeat responses that lead to positive outcomes, and they tend not to repeat responses that lead to neutral or negative outcomes. He demonstrated this with animals in a "Skinner box," showing remarkable control over behavior by manipulating outcomes. These principles were later applied to complex human behaviors in various settings.
◦ Free Will: In his book Beyond Freedom and Dignity (1971), Skinner asserted that all behavior is fully governed by external stimuli and that free will is an illusion, with our actions determined by predictable, lawful principles rather than conscious decisions.
• Carl Rogers & Abraham Maslow/Humanism
◦ Emergence: Humanism emerged in the 1950s as a reaction against the "dehumanizing" aspects of behaviorism and psychoanalytic theory. Critics argued that these older theories failed to recognize the unique qualities of human behavior, such as freedom and potential for growth.
◦ Core Philosophy: Humanism is a theoretical orientation that emphasizes the unique qualities of humans, especially their freedom and their potential for personal growth. Humanists take an optimistic view of human nature, believing people are not merely pawns of their animal heritage or environmental circumstances. They also argued that research on animals has little relevance for understanding human behavior.
◦ Carl Rogers: Argued that human behavior is governed primarily by each individual's sense of self, or "self-concept".
◦ Abraham Maslow: Along with Rogers, Maslow maintained that psychologists must consider the human drive toward personal growth and the basic need for people to evolve and fulfill their potential to fully understand behavior.
• Nature vs. Nurture
◦ The Debate: This age-old question concerns whether behavior is determined mainly by genetic inheritance ("nature") or by environment and experience ("nurture"). Historically, it was framed as an "all-or-none" proposition.
◦ Early Stances: John B. Watson argued behavior was governed entirely by the environment. Sir Francis Galton, in contrast, focused on genetic inheritance.
◦ Modern View: Most psychologists today agree that heredity and environment jointly influence behavior. A century of research shows that genetics and experience interact to shape individuals' intelligence, temperament, personality, and susceptibility to many psychological disorders. The answer to whether people are "born or made" is "Both".
◦ Complexity: The debate continues regarding the relative influence of genetics and experience and the complex ways they interact to mold behavior. Genes confer dispositions, not destinies; they influence physiological makeup, which in turn influences traits, but always in an environmental context.
◦ Epigenetics: This emerging field further demonstrates the intertwined nature of genetic and environmental factors, showing that environmental events can chemically "dampen or silence" gene expression, leading to alterations in traits, health, and behavior, and these changes can be passed to subsequent generations.
• Definition of Psychology
◦ Historical Context: The term "psychology" originated from Greek words "psyche" (soul/spirit/mind) and "logos" (study of a subject), acquiring its literal meaning "the study of the mind" by the early 18th century.
◦ Wundt's Definition: The scientific study of conscious experience.
◦ Watson's Redefinition: The science of behavior, advocating to abandon consciousness.
◦ Modern Definition: Psychology is formally defined as the science that studies behavior and the physiological and cognitive processes that underlie behavior, and it is the profession that applies the accumulated knowledge of this science to practical problems. This modern definition encompasses the study of overt behavior, as well as mental and physiological processes.
• Cognition
◦ Definition: Cognition refers to the mental processes involved in acquiring knowledge, including thinking or conscious experience.
◦ Historical Shift: For decades, behaviorism's dominance discouraged the study of "unobservable" mental processes, leading to little interest in cognition.
◦ Renewed Interest: During the 1950s and 1960s, interest in cognition slowly re-emerged, partly inspired by the information-processing capabilities of newly invented computers, drawing parallels between computers and human cognition.
◦ Cognitive Perspective: Cognitive theorists argue that psychology must include the study of internal mental events to fully understand human behavior, as mental processes clearly influence how we behave. They have developed methods to study cognitive processes scientifically.
◦ Dominance: The cognitive approach has become the dominant perspective in contemporary psychology, generating more published articles than any other perspective since around 1975.
• Applied Psychology Specialties: Clinical, Counseling, Industrial-Organizational, etc.
◦ Psychology has a highly practical side, with many psychologists providing professional services. This broad area is known as applied psychology.
◦ Clinical Psychology: This is the branch of psychology concerned with the diagnosis and treatment of psychological problems and disorders. It was the first applied arm of psychology to achieve prominence. Its role dramatically expanded during and after World War II, as academic psychologists were needed to screen recruits and treat traumatized soldiers, leading to significant funding for training programs. Clinical psychology is currently the most widely practiced professional specialty. Clinical psychologists earn doctoral degrees (Ph.D., Ed.D., or Psy.D.) and take a nonmedical approach to problems, contrasting with psychiatrists who are medical doctors (M.D.).
◦ Counseling Psychology: This is one of the four main professional specialties within applied psychology. (Specific definition not provided in source).
◦ School Psychology: This is another of the four main professional specialties, focusing on psychological services in educational settings. (Specific definition not provided in source).
◦ Industrial/Organizational Psychology: This is also one of the four main professional specialties, applying psychological principles to the workplace and organizational settings. (Specific definition not provided in source).
◦ Other Research Areas: While not "applied specialties," the sources also list major research areas: developmental, social, experimental, physiological, cognitive, personality, psychometrics, educational, and health psychology.
• 7 Key Themes: Empirical, theoretically diverse, socio-historical context, multiple causation, cultural heritage, heredity & environment, subjectivity
◦ These seven fundamental themes provide threads of continuity across various areas of psychology.
◦ 1. Psychology Is Empirical: This theme means that psychology's conclusions are based on direct observation rather than on reasoning, speculation, traditional beliefs, or common sense. It emphasizes the commitment to the scientific method, demands data and documentation, and fosters a healthy skepticism.
◦ 2. Psychology Is Theoretically Diverse: Psychology is characterized by many competing points of view. This diversity exists because no single theory can adequately explain everything about behavior, and different theories may focus on different aspects. Contemporary psychologists increasingly recognize theoretical diversity as a strength, as it stimulates productive research and provides a more complete understanding when problems are approached from multiple perspectives.
◦ 3. Psychology Evolves in a Sociohistorical Context: This theme highlights the interconnections between what happens in psychology and what happens in society at large. Trends, issues, and values in society influence psychology's evolution (e.g., Freud's ideas influenced by cultural suppression of sexuality, WWII spurring clinical psychology's growth, 1960s societal interest in altered consciousness leading to psychological research on drugs, meditation, and hypnosis). Conversely, progress in psychology affects societal trends and values (e.g., mental testing, parenting styles).
◦ 4. Behavior Is Determined by Multiple Causes (Multifactorial Causation): This theme recognizes that behavior is exceedingly complex and that most aspects of behavior are governed by a complex network of interacting factors, rather than single causes. Examples include academic performance, the development of schizophrenia (involving neurotransmitter abnormalities, brain structure, and genetic vulnerability), and the effects of jet lag, sleep deprivation, or psychoactive drugs, all dependent on multiple interacting factors.
◦ 5. Behavior Is Shaped by Cultural Heritage: Culture refers to the widely shared customs, beliefs, values, norms, institutions, and other products of a community that are transmitted socially across generations. It encompasses everything from dietary habits and legal systems to family roles and spiritual beliefs. Much of cultural heritage is "invisible" and taken for granted, but it has a pervasive impact on thoughts, feelings, and behavior. Both differences and similarities in behavior occur across cultures, and considering cultural determinants is crucial for a sound understanding of human behavior. For example, sleep habits and dream interpretation vary culturally.
◦ 6. Heredity and Environment Jointly Influence Behavior: This theme underscores that both genetic inheritance ("nature") and experience ("nurture") are important and interact to influence individuals' traits such as intelligence, temperament, personality, and susceptibility to psychological disorders. Genes confer dispositions, not destinies, and their effects are always intertwined with environmental context. The field of epigenetics further demonstrates this interplay, showing how environmental events can alter gene expression, and these changes can even be heritable.
◦ 7. People’s Experience of the World Is Highly Subjective: This theme emphasizes that perception is not a passive process; instead, individuals actively process incoming stimulation, selectively focusing on some aspects while ignoring others, and imposing organization on stimuli. This leads to personalized and subjective experiences, as demonstrated by studies like Hastorf and Cantril's (1954) football game experiment, where students saw what they wanted to see. This subjectivity helps explain distortions in memory, overconfidence, and the rationalization of prejudice. It also manifests in phenomena like placebo effects and experimenter bias.
• Natural Selection & Evolutionary Psychology
◦ Evolutionary Psychology: A theoretical perspective that emerged in the mid-to-late 1980s, which examines behavioral processes in terms of their adaptive value for members of a species over the course of many generations. It is based on the assumption that a species' typical patterns of behavior often reflect evolutionary solutions to adaptive problems.
◦ Basic Premise: The fundamental premise is that natural selection favors behaviors that enhance organisms' reproductive success—that is, behaviors that help pass on genes to the next generation.
◦ Darwin's Insights: Charles Darwin identified natural selection as the engine of evolution. His explanation centered on four insights: (1) organisms vary in endless ways; (2) some characteristics are heritable; (3) organisms produce more offspring than resources allow, leading to competition; and (4) heritable traits that contribute to survival or reproductive success will lead to more offspring, thus increasing their prevalence over generations.
◦ Fitness: In evolutionary theory, fitness refers to the reproductive success (number of descendants) of an individual organism relative to the average reproductive success in the population.
◦ Adaptations: The key products of natural selection are adaptations, which are inherited characteristics that increased in a population because they helped solve a problem of survival or reproduction during the time they emerged. These adaptations can be physical (e.g., woodpecker beaks) or behavioral (e.g., rats' caution with new foods, grasshopper hiding behavior, female mate choice). Sometimes, adaptations linger even if no longer adaptive in contemporary environments (e.g., taste preference for fatty foods).
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Chapter 2: The Research Enterprise in Psychology
• Steps in Research Scientific investigations are systematic and follow an orderly pattern. The five steps are:
1. Formulate a Testable Hypothesis: The first step is to translate a theory or intuitive idea into a precise, testable hypothesis. This requires providing operational definitions for all relevant variables.
2. Select the Research Method and Design the Study: Researchers choose the most appropriate and practical research method (e.g., experiment, case study, survey, naturalistic observation) based on the research question. Detailed plans are made, including recruiting participants and determining sample size.
3. Collect the Data: This step involves implementing data collection techniques, such as direct observation, questionnaires, interviews, psychological tests, physiological recordings, or archival records.
4. Analyze the Data and Draw Conclusions: Observations are converted into numbers, and statistics are used to analyze the data to determine whether the hypotheses are supported.
5. Report the Findings: The final step is to write a concise summary of the study and its findings, typically submitted to a scientific journal for publication. This report undergoes a demanding peer-review process by experts to ensure reliability and high-quality research.
• Experimental Design
◦ Definition: An experiment is a research method in which the investigator manipulates a variable under carefully controlled conditions and observes whether any changes occur in a second variable as a result.
◦ Purpose: It is a powerful procedure because it allows researchers to detect cause-and-effect relationships between variables. Psychologists prefer this method whenever possible due to this strength.
◦ Components: Typically involves an independent variable, a dependent variable, and at least an experimental and control group.
◦ Limitations: Experiments can be artificial due to the need for strict control, and they cannot be used to explore all research questions, especially those involving ethical concerns or practical impossibilities of manipulation (e.g., diet during pregnancy, or upbringing).
• Hypothesis(relationship b/n variables /Theory (ideas explaining what you think is going to happen)
◦ Hypothesis: A tentative statement about the relationship between two or more variables. Hypotheses are specific predictions derived from a broader theory. To be testable, a scientific hypothesis must be formulated precisely, and its variables must be clearly defined.
◦ Theory: A system of interrelated ideas used to explain a set of observations. Theories link apparently unrelated observations, permitting psychologists to move from describing behavior to understanding it. They also guide future research by generating new predictions and lines of inquiry. A scientific theory must be testable, but because theories are often too complex, investigators test one or two specific hypotheses derived from the theory. Confidence in a theory grows with supporting findings and diminishes with contradictory ones, leading to revision or discarding.
• Operational Definition (Whats gonna be done to the variable)
◦ An operational definition describes the actions or operations that will be used to measure or control a variable in a study. These definitions establish precisely what is meant by each variable within the context of a particular study, and they may differ from common dictionary definitions. For example, in a study on attraction, "attraction" might be operationally defined by ratings on a 1-9 scale for overall attractiveness, sexual desirability, dating interest, and willingness to spend money on a date.
• Independent variable, Dependent Variable
◦ Independent Variable (IV): This is the condition or event that an experimenter varies or manipulates in order to see its impact on another variable. It is the variable hypothesized to cause some effect on the dependent variable.
◦ Dependent Variable (DV): This is the variable that is thought to be affected by the manipulation of the independent variable. In psychology studies, the dependent variable is typically a measurement of some aspect of the subjects' behavior. It is called "dependent" because its value is believed to depend on the independent variable.
◦ Example: In Schachter's anxiety and affiliation study, the independent variable was the participants' anxiety level (manipulated as high or low anxiety), and the dependent variable was their desire to be with others (affiliation).
• Experimental vs. Control Group
◦ Experimental Group: Consists of the subjects who receive some special treatment in regard to the independent variable.
◦ Control Group: Consists of similar subjects who do not receive the special treatment given to the experimental group.
◦ Purpose: The crucial aspect is that these two groups must be very similar in all respects except for the manipulation of the independent variable. This allows researchers to isolate the effect of the independent variable on the dependent variable, attributing any differences in the dependent variable between the groups to the independent variable.
• Placebo
◦ Definition: A substance that resembles a drug but has no actual pharmacological effect.
◦ Use in Research: Placebos are used in studies (especially those assessing medication effectiveness) to control for the effects of subjects' expectations.
◦ Placebo Effects: Occur when participants' expectations lead them to experience some change even though they receive empty, fake, or ineffectual treatment. These effects can be powerful, influencing perceptions and behavior, such as individuals showing signs of intoxication from non-alcoholic beverages if they believe they are drinking alcohol. Social influence can also moderate placebo effects. Researchers assess the role of placebo effects by including a placebo condition in studies.
• Sample vs. Population (pretty much same shi tbh)
◦ Sample: The collection of subjects selected for observation in an empirical study. Subset of population
◦ Population: The much larger collection of animals or people (from which the sample is drawn) that researchers want to generalize about.
◦ Relationship: Empirical research always involves making statistical inferences about a population based on a sample. The representativeness of the sample to the population is critical for the generalizability of findings.
• Replication (doing smth again to see if you get the same results)
◦ Definition: The repetition of a study to see whether the earlier results are duplicated.
◦ Importance: Replication is a fundamental aspect of the scientific enterprise, as it helps science identify and purge inaccurate findings and build confidence in reliable results.
◦ Challenges: Inconsistent findings can occur due to slight variations across studies in sampling, procedures, and measures. Recent discussions about a "replication crisis" in psychology have stimulated efforts to improve research practices and reproducibility.
◦ Meta-analysis: A technique that combines the statistical results of many studies on the same question, providing an estimate of the size and consistency of a variable's effects, and helping to make sense of inconsistent results across studies.
• Descriptive vs. Inferential Statistics
◦ Descriptive Statistics (Raw numerical data): Although not explicitly defined in the provided text, the concept is implied when discussing how "The observations made in a study are usually converted into numbers, which constitute the raw data of the study". Descriptive statistics are used to organize and summarize these raw data.
◦ Inferential Statistics (making an inference on a population based off of results from a sample): Not explicitly defined. However, the text refers to "making statistical inferences about a population based on a sample". Inferential statistics allow researchers to draw conclusions about a population based on data from a sample, often used to determine if hypotheses have been supported.
• Measures of Central Tendency: Mean Median Mode
◦ These terms are not explicitly defined or discussed in the provided sources.
• Measures of Variability: Standard deviation
◦ Measure of the amount of variation of a set of values
Low standard deviation means the values are close to the mean
High standard deviation means values are far from mean
• Subjects/Participants (same meaning diff wrd)
◦ These terms are used interchangeably and refer to the persons or animals whose behavior is systematically observed in a study.
• Random Assignment
◦ Definition: Occurs when all subjects have an equal chance of being assigned to any group or condition in the study.
◦ Purpose: This is a routine procedure in psychological research, especially experiments, designed to ensure that the experimental and control groups are similar in most ways, thereby controlling for extraneous variables and preventing confounding.
◦ Distinction: It is important not to confuse random assignment with random sampling; random assignment is common in experiments, while random sampling is relatively infrequent.
• "Statistically significant"
◦ This phrase is used to describe a result where the observed difference or relationship between variables is unlikely to be due to chance. For example, the red blouse led to "significantly higher attractiveness ratings" than the blue blouse, meaning the difference was likely real and not random. This is determined through statistical analyses.
• "Reasonable representative" (results from the sample speaks for population)
◦ This phrase is not a formally defined term in the sources, but it refers to the goal in research to have a sample that adequately reflects the characteristics of the larger population from which it was drawn. Researchers strive for representative samples, although achieving truly random sampling (where everyone in the population has an equal chance of being selected) can be impractical.
• Case study, Survey, Naturalistic Observation
◦ Case Study: An in-depth investigation of an individual subject. It can involve various data collection techniques such as interviewing the subject and those close to them, direct observation, examining records, and psychological testing. Case studies are particularly well-suited for investigating the roots of psychological disorders and the efficacy of therapeutic practices, and they can provide compelling real-life illustrations. The main weakness is their high subjectivity, as investigators may selectively focus on information that aligns with their expectations.
◦ Survey: Researchers use questionnaires or interviews to gather information about specific aspects of participants' background, attitudes, beliefs, or behavior. Surveys are useful for obtaining data on hard-to-observe behaviors and collecting information from large samples. However, their major weakness is their reliance on self-report data, which can be distorted by intentional deception, wishful thinking, memory lapses, and social desirability bias. Declining response rates in surveys can also increase the likelihood of sampling bias.
◦ Naturalistic Observation: This method involves a researcher engaging in careful observation of behavior without intervening directly with the subjects in their natural environment. Behavior is allowed to unfold naturally. Its major strength is that it allows for the study of behavior under conditions less artificial than experiments, making it a good starting point when little is known about a behavior. It is also effective for studying animal behavior. A key problem is reactivity, where a subject's behavior is altered by the presence of an observer. It can also be difficult to translate naturalistic observations into numerical data for precise statistical analysis.
• Correlation, coefficient, positive vs. negative
◦ Correlation: An association or link that exists when two variables are related to each other.
◦ Positive Correlation: Indicates that two variables co-vary (change together) in the same direction. High scores on one variable are associated with high scores on the other, and low with low (e.g., high school GPA and college GPA).
◦ Negative Correlation: Indicates that two variables co-vary in opposite directions. High scores on one variable are associated with low scores on the other (e.g., frequent absences and low exam scores).
◦ Correlation Coefficient: A numerical index of the degree of relationship between two variables. It ranges from 0 to +1.00 (for positive correlations) or 0 to -1.00 (for negative correlations). A coefficient near zero indicates no relationship, while +1.00 or -1.00 indicates a perfect relationship. The closer the coefficient is to +1.00 or -1.00, the stronger the relationship (e.g., -.75 is stronger than +.40).
◦ Prediction vs. Causation: While a strong correlation allows for prediction of one variable based on another, it does not tell us whether a cause-and-effect relationship exists between the two variables. This is known as the "third-variable problem," where two correlated variables might both be caused by an unmeasured third variable (e.g., extraversion leading to both social activity and happiness).
• Social desirability
◦ This is a bias in self-report data where participants tend to give socially approved information about themselves, rather than truthful responses, distorting the data. It is a problem associated with methods like surveys and anecdotal evidence.
• Self-report
◦ A category of data collection techniques (such as questionnaires and interviews) where subjects provide verbal accounts about specific aspects of their behavior, attitudes, beliefs, or background. A major weakness of surveys, self-report data can be distorted by intentional deception, wishful thinking, memory lapses, or social desirability bias.
• Double-Blind Method
◦ A research strategy designed to neutralize the problems associated with experimenter bias. In a double-blind procedure, neither the subjects nor the experimenters know which subjects are in the experimental or control groups. A separate member of the research team tracks group assignments, ensuring that neither the participants' expectations (placebo effects) nor the researchers' expectations (experimenter bias) can unintentionally influence the results.
• Experimenter Bias
◦ Definition: Occurs when a researcher’s expectations or preferences about the outcome of a study influence the results obtained.
◦ Manifestation: This bias can manifest in subtle ways, such as researchers unintentionally making errors in recording subjects' responses that favor their hypothesis, or unconsciously influencing subjects' behavior through nonverbal signals (e.g., smiles, nods).
◦ Control: The problems associated with experimenter bias can be neutralized through the use of a double-blind procedure.
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Chapter 3: The Biological Bases of Behavior
• Neurons
◦ Definition: Individual cells in the nervous system that receive, integrate, and transmit information. They are the basic links that permit communication within the nervous system. The vast majority communicate only with other neurons, but a minority receive signals from sensory organs or carry messages to muscles and glands.
◦ Role: Handle the bulk of information processing in the nervous system.
• Glia
◦ Definition: Cells found throughout the nervous system that provide various types of support for neurons.
◦ Functions: Traditionally known to supply nourishment to neurons, help remove waste products, and provide insulation around many axons (forming myelin sheaths). They also play a complicated role in the development of the nervous system in the human embryo.
◦ New Research: Recent discoveries suggest glia may also send and receive chemical signals, modulating neuronal activity by dampening or amplifying synaptic activity, or shielding synapses from surrounding neuronal "chatter". This implies they play an important role in information processing beyond just support.
◦ Disorders: Dysfunction in glial cells has been implicated in schizophrenic disorders, some forms of depressive disorders, Alzheimer's disease, chronic pain, the body's stress response, some types of epilepsy, and congenital problems in fetal alcohol syndrome.
• Soma
◦ Definition: The cell body of a neuron.
◦ Contents: Contains the cell nucleus and much of the chemical machinery common to most cells. Information flows into the soma from the dendrites.
• Dendrites
◦ Definition: Branched, feeler-like structures that are the parts of a neuron specialized to receive information.
◦ Structure: Often form extensive "dendritic trees" because most neurons receive information from many other cells. Information flows from dendrites into the cell body.
• Axons
◦ Definition: A long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands.
◦ Characteristics: Can be quite long (several feet) and may branch to communicate with multiple other cells.
• Myelin Sheath
◦ Definition: An insulating material, a white, fatty substance, that encases some axons. It is derived from special types of glial cells.
◦ Function: Primarily functions to speed up the transmission of signals along axons. Also stabilizes axon structure and connectivity patterns in neural networks by preventing axons from sprouting in new directions.
◦ Structure: Not all axons are myelinated, and myelination can be segmented.
• Multiple Sclerosis
◦ Link: The loss of muscle control associated with multiple sclerosis is due to a degeneration of myelin sheaths. When myelin sheaths deteriorate, signals may not be transmitted effectively.
• Synapse
◦ Definition: A junction where information is transmitted from one neuron to another. Neurons do not physically touch but are separated by a synaptic cleft.
◦ Synaptic Cleft: The microscopic gap between the terminal button of one neuron (presynaptic neuron) and the cell membrane of another neuron (postsynaptic neuron). Signals must cross this gap.
◦ Transmission Process:
1. An action potential arrives at an axon's terminal buttons.
2. This triggers the release of neurotransmitters (chemical messengers) from synaptic vesicles (small sacs) within the terminal buttons into the synaptic cleft.
3. Neurotransmitters diffuse across the cleft and bind to specific receptor sites on the postsynaptic cell membrane, like a key fitting a lock.
4. This binding causes a postsynaptic potential (PSP), a voltage change in the receiving cell membrane. PSPs are graded (vary in size) and either excitatory (increase likelihood of firing an action potential) or inhibitory (decrease likelihood of firing).
5. Neurotransmitters then drift away or are inactivated by enzymes. Most are reabsorbed into the presynaptic neuron via reuptake, allowing synapses to recycle materials.
◦ Synaptic Pruning: The nervous system forms more synapses than needed and then gradually eliminates the less-active ones. This elimination of old or less-active synapses is called synaptic pruning, a key process in forming and strengthening neural networks crucial for communication.
◦ Neural Networks: Neurons are interlinked in complex networks, and perceptions, thoughts, and actions depend on patterns of neural activity in these networks.
• Neurotransmitters: Ach, Monoamines, dopamine, endorphins
◦ General Role: Chemicals that transmit information from one neuron to another. They are fundamental to behavior, influencing everything from muscle movements to moods and mental health.
◦ Specificity: Specific neurotransmitters function at specific kinds of synapses, binding only to receptor sites that fit their molecular structure. This variety and specificity reduce crosstalk, making communication more precise.
◦ Acetylcholine (ACh)
▪ Functions: The only transmitter between motor neurons and voluntary muscles, essential for all voluntary movements (walking, talking, breathing). Also contributes to attention, arousal, and memory.
▪ Disorders/Issues: An inadequate supply of ACh in certain brain areas is associated with memory losses in Alzheimer's disease. Drug treatments for Alzheimer's aim to amplify ACh activity. Botox treatments temporarily reduce wrinkles by blocking ACh receptors, paralyzing muscles.
◦ Monoamines
▪ Definition: A group of three neurotransmitters: dopamine, norepinephrine, and serotonin.
▪ Regulation: Neurons using these transmitters regulate many aspects of everyday behavior. Abnormal levels are related to psychological disorders.
▪ Norepinephrine (NE): Contributes to the modulation of mood and arousal. Low levels of activation at NE synapses are related to major depression. Cocaine and amphetamines elevate NE activity.
▪ Serotonin: Involved in the regulation of sleep and wakefulness, eating, and aggression. Abnormalities in serotonin circuits are implicated in depressive disorders, obsessive-compulsive disorders, and eating disorders. Antidepressant drugs like Prozac affect serotonin circuits.
◦ Dopamine (DA)
▪ Functions: Primarily contributes to the control of voluntary movement. Also involved in reward, pleasure, memory, pain perception, attention, learning, and arousal, though the "pleasure chemical" characterization is an oversimplification.
▪ Disorders/Issues: The degeneration of DA-releasing neurons in the midbrain causes Parkinson's disease. Overactivity at DA synapses in certain brain regions is the neurochemical basis for schizophrenia (dopamine hypothesis). Cocaine and amphetamines elevate DA activity, leading to their stimulant and rewarding effects, and dysregulation in dopamine pathways is key to drug craving and addiction.
◦ GABA (gamma-aminobutyric acid)
▪ Functions: Serves as a widely distributed inhibitory transmitter. It has inhibitory effects at virtually all synapses where it is present, responsible for much of the inhibition in the central nervous system. Contributes to the regulation of anxiety and sleep/arousal.
▪ Disorders/Issues: Disturbances in GABA circuits may contribute to anxiety disorders. Antianxiety drugs like Valium work at GABA synapses.
◦ Endorphins
▪ Definition: Internally produced chemicals that resemble opiate drugs in structure and effects.
▪ Discovery: Discovered after researchers found that morphine binds to specific receptors in the brain, suggesting the body produced its own opiate-like substances.
▪ Functions: Play a role in pain relief (modulating pain), the body's response to stress, and the regulation of eating behavior. Also linked to the euphoric "runner's high".
• Agonist vs. Antagonist
◦ These terms are not explicitly defined in the provided sources.
• Parkinson’s disease
◦ Cause: Caused by the degeneration of dopamine-releasing neurons in a structure located in the midbrain.
◦ Symptoms: Marked by tremors, muscular rigidity, reduced control over voluntary movements, and associated problems.
◦ Link to RBD: A majority of people diagnosed with REM sleep behavior disorder (RBD) eventually develop neurodegenerative disorders, especially Parkinson's disease, with RBD symptoms sometimes preceding Parkinson's by as much as 10 years.
• Schizophrenia
◦ Neurochemical Link: The dopamine hypothesis asserts that overactivity at dopamine synapses in certain regions of the brain is the neurochemical basis for schizophrenia.
◦ Brain Structure Link: CT and MRI scans have found abnormalities in brain structure in people diagnosed with schizophrenia.
◦ Genetic Link: Evidence indicates genetic vulnerability to schizophrenia, though people inherit a predisposition rather than the disorder itself, with environmental factors playing a role in its manifestation.
◦ Other Links: Dysfunction in glial cells may contribute to its development. Cannabis use can trigger psychotic illness in individuals with a genetic vulnerability.
• Brain Imaging (CT, MRI, PET, fMRI)
◦ CT (Computerized Tomography) Scan:
▪ Method: A computer-enhanced X-ray of brain structure. Multiple X-rays are combined to create a vivid image of a horizontal slice of the brain.
▪ Purpose: Examines brain structure. Has found abnormalities in brain structure in mental illnesses like schizophrenia.
◦ MRI (Magnetic Resonance Imaging) Scan:
▪ Method: Uses magnetic fields, radio waves, and computerized enhancement to map out brain structure.
▪ Purpose: Provides much better images of brain structure than CT scans, producing high-resolution, three-dimensional pictures of the brain. Used to find abnormalities in brain structure, e.g., in schizophrenia.
◦ PET (Positron Emission Tomography) Scan:
▪ Method: Uses radioactive markers to map chemical activity in the brain over time.
▪ Purpose: Provides a color-coded map indicating which areas of the brain become active during various tasks (e.g., clenching a fist, singing, thinking). Maps brain activity rather than just structure.
◦ fMRI (Functional Magnetic Resonance Imaging):
▪ Method: Newer variations of MRI technology that monitor blood flow and oxygen consumption in the brain.
▪ Purpose: Identifies areas of high activity with vastly greater precision than PET scans, mapping actual brain activity over time. Used to identify patterns of brain activity during creative thinking, complex decision making (gambling), reactions to alcoholic beverages, and imagining future events.
• All-Or-None Law
◦ Definition: The neural impulse (action potential) is an all-or-none proposition, meaning either the neuron fires or it doesn't, and its action potentials are all the same size.
◦ Mechanism: Weaker stimuli do not produce smaller action potentials, nor do stronger stimuli evoke larger ones. Neurons convey information about stimulus strength by varying the rate at which they fire action potentials (e.g., dim light vs. brighter light).
• CNS (Central Nervous System)
◦ Definition: The portion of the nervous system that lies within the skull and spinal column.
◦ Components: Consists of the brain and the spinal cord.
◦ Protection/Nourishment: Bathed in cerebrospinal fluid (CSF), which nourishes the brain and provides a protective cushion. Substances from the blood must cross the blood-brain barrier (a semipermeable membrane) to enter the CSF.
• PNS (Peripheral Nervous System)
◦ Definition: Made up of all those nerves that lie outside the brain and spinal cord.
◦ Nerves: Bundles of neuron fibers (axons) routed together.
◦ Subdivisions: Subdivided into the somatic nervous system and the autonomic nervous system.
• ANS (Autonomic Nervous System)
◦ Definition: Made up of nerves that connect to the heart, blood vessels, smooth muscles, and glands.
◦ Function: Controls automatic, involuntary, visceral functions that people don't normally think about, such as heart rate, digestion, and perspiration. Mediates much of the physiological arousal during emotions (e.g., fight-or-flight response).
◦ Control: Ultimately controlled by the central nervous system, particularly the hypothalamus.
• SNS (Somatic Nervous System)
◦ Definition: Made up of nerves that connect to voluntary skeletal muscles and to sensory receptors.
◦ Function: Allows you to feel the world and move around in it. Carries information from receptors in skin, muscles, and joints to the CNS, and carries commands from the CNS to muscles.
◦ Nerve Fibers: Contains afferent nerve fibers (carry information inward to CNS from periphery) and efferent nerve fibers (carry information outward from CNS to periphery). Somatic nerves are "two-way streets".
• Sympathetic vs. Parasympathetic NS
◦ Sympathetic Division:
▪ Function: The branch of the ANS that mobilizes the body’s resources for emergencies. It creates the "fight-or-flight" response.
▪ Effects: Slows digestive processes, drains blood from the periphery, sends signals to adrenal glands to release hormones for exertion. Leads to increased heart rate, faster breathing, surging blood pressure, goosebumps, sweating (autonomic arousal).
◦ Parasympathetic Division:
▪ Function: The branch of the ANS that generally conserves bodily resources.
▪ Effects: Activates processes that allow the body to save and store energy, such as slowing heart rate, reducing blood pressure, and promoting digestion.
• The Brain: Cerebrum, corpus callosum, hemispheres, Lobes (occipital, parietal, temporal, frontal)
◦ Cerebrum:
▪ Definition: The largest and most complex part of the human brain, responsible for our most complex mental activities, including learning, remembering, thinking, and consciousness.
▪ Cerebral Cortex: The convoluted outer layer of the cerebrum, folded to pack a large surface area into the skull.
◦ Corpus Callosum:
▪ Definition: A thick band of fibers that connects the two cerebral hemispheres.
▪ Function: The major structure for communication between the right and left halves of the cerebrum. Cutting it (split-brain surgery) reduces epileptic seizures and reveals hemispheric specialization. Einstein's brilliance may have been linked to exceptional connectivity in his corpus callosum.
◦ Hemispheres (Cerebral Hemispheres):
▪ Definition: The right and left halves of the cerebrum, separated by the longitudinal fissure.
▪ Contralateral Control: Each hemisphere's primary connections are to the opposite side of the body (left hemisphere controls right side, right hemisphere controls left side). Visual input is also crisscrossed (right visual field to left hemisphere, left visual field to right hemisphere).
▪ Specialization (Lateralization):
• Left Hemisphere: Usually better on tasks involving verbal processing, such as language, speech production (Broca's area), language comprehension (Wernicke's area), reading, writing, math, and logic. Historically considered "dominant".
• Right Hemisphere: Exhibits superiority on many tasks involving nonverbal processing, such as most spatial tasks (e.g., mental rotation, navigation, recognizing faces, arranging blocks), musical tasks, and visual recognition tasks (including perception of emotions).
▪ Interactions: While specialized, the hemispheres are constantly collaborating, with highly dynamic interhemispheric communication and coordination. Specialization is not absolute and can vary (e.g., in left-handed people or accomplished musicians who show more bilateral organization). The idea of "left-brained" or "right-brained" individuals is largely mythical and not supported by brain-imaging research.
◦ Lobes: Each cerebral hemisphere is divided into four lobes by deep fissures.
▪ Occipital Lobe:
• Location: At the back of the head.
• Function: Includes the primary visual cortex, where most visual signals are sent and visual processing begins.
▪ Parietal Lobe:
• Location: Forward of the occipital lobe.
• Function: Includes the primary somatosensory cortex, which registers the sense of touch, receiving signals from different body regions. Also involved in integrating visual input and monitoring the body’s position in space.
▪ Temporal Lobe:
• Location: Lies below the parietal lobe, near the temples.
• Function: Contains the primary auditory cortex, devoted to auditory processing. Damage to an area in the left temporal lobe (Wernicke's area) can impair speech and language comprehension.
▪ Frontal Lobe:
• Location: The largest lobe, at the front of the brain.
• Function: Contains the primary motor cortex, which controls muscle movements. The amount of motor cortex allocated to a body part depends on the diversity and precision of its movements (e.g., more for fingers, lips, tongue). The prefrontal cortex (in front of the motor cortex) is involved in decision making, key aspects of self-control, and is thought to house an "executive control system" for organizing and directing thought processes.
• Broca’s vs. Wernicke’s Area
◦ Both are critical language centers primarily located in the left hemisphere.
◦ Broca's Area: Located in the frontal lobe. Plays an important role in the production of speech. Damage here leads to speech deficits.
◦ Wernicke's Area: Identified in the temporal lobe. Damage here usually leads to problems with the comprehension of language.
• Medulla
◦ Location: Found in the lower part of the hindbrain, attached to the spinal cord.
◦ Function: Controls largely unconscious but essential functions, such as breathing, maintaining muscle tone, and regulating circulation.
• Pons
◦ Location: Found in the lower part of the hindbrain, includes a bridge of fibers connecting the brainstem with the cerebellum.
◦ Function: Contains several clusters of cell bodies involved with sleep and arousal.
• Hindbrain, Midbrain, Forebrain
◦ Overall Structure: The brain is traditionally divided into three major regions: hindbrain, midbrain, and forebrain. The brainstem, from which the rest of the brain "flowers," lies at the lower end where the spinal cord joins. Functions generally progress from basic bodily processes (lower regions) to "higher" mental processes (upper regions).
◦ Hindbrain:
▪ Location: Lower part of the brainstem.
▪ Structures: Includes the medulla, pons, and cerebellum.
▪ Functions: Controls vital involuntary functions like breathing and circulation, as well as coordination of movement and equilibrium.
◦ Midbrain:
▪ Location: Segment of the brainstem between the hindbrain and forebrain.
▪ Structures: Contains an area concerned with integrating sensory processes (vision, hearing). An important system of dopamine-releasing neurons projecting to higher brain centers originates here, involved in voluntary movements. The degeneration of a midbrain structure causes Parkinson's disease.
▪ Reticular Formation: Runs through both the hindbrain and midbrain, contributing to modulation of muscle reflexes, breathing, pain perception, and most notably, the regulation of sleep and wakefulness (ascending fibers contribute to arousal).
◦ Forebrain:
▪ Location: Largest and most complex region of the brain, atop the brainstem.
▪ Structures: Encompasses the thalamus, hypothalamus, limbic system, and cerebrum. The thalamus, hypothalamus, and limbic system form the core, with the cerebrum above them.
▪ Functions: Seat of complex thought and higher mental activities.
• Amygdala
◦ Location: Part of the limbic system, near the base of the forebrain.
◦ Function: Plays a central role in the learning of fear responses and the processing of other basic emotions. Destruction of the amygdala can lead to an inability to experience fear.
• Hippocampus
◦ Location: Part of the limbic system, near the base of the forebrain.
◦ Function: Clearly plays a role in memory processes, particularly the consolidation of memories for factual information (converting information into a durable memory code). Involved in spatial learning. Adult brains can form new neurons (neurogenesis) in the hippocampus, which may be important for spatial learning and memory.
• Cerebellum
◦ Location: Part of the hindbrain, a relatively large and deeply folded structure adjacent to the back surface of the brainstem.
◦ Traditional Function: Involved in the coordination of movement and is critical to the sense of equilibrium, or physical balance. Plays a key role in executing precise and accurately timed muscular movements. Damage can disrupt motor skills.
◦ Newer Functions: Recent discoveries suggest involvement in perception, recognition, and recall of emotions, and various types of language processing tasks. Contains 80% of the brain's neurons despite being only 10% of its volume.
• Hypothalamus
◦ Location: A structure found near the base of the forebrain, lying beneath the thalamus ("hypo" meaning under).
◦ Function: Involved in the regulation of basic biological needs, often referred to as the "four F's": fighting, fleeing, feeding, and "mating". Also plays a major role in controlling the autonomic nervous system and exerts influence over virtually every major subdivision of the CNS. Has intimate connections with the pituitary gland, controlling much of the endocrine system.
• Thalamus
◦ Location: A structure in the forebrain, near the top of the brainstem.
◦ Function: A relay station through which all sensory information (except smell) must pass to get to the cerebral cortex. Made up of clusters of cell bodies, each relaying sensory information to a particular part of the cortex. Also plays an active role in integrating information from various senses.
• Endocrine System: glands (pituitary, adrenals), hormones, etc.
◦ Definition: The body's second communication system, consisting of glands that secrete chemicals (hormones) into the bloodstream to help control bodily functioning.
◦ Hormones: The chemical messengers released by endocrine glands. Unlike neurotransmitters, they can't match the speed of neural transmission and tend to be less specific, often acting on many target cells. Hormone release is typically pulsatile (brief bursts several times a day).
◦ Control: Much of the endocrine system is controlled by the nervous system, specifically the hypothalamus, which has intimate connections with the pituitary gland.
◦ Pituitary Gland: A pea-sized gland often called the "master gland" of the endocrine system, as it releases a great variety of hormones that stimulate actions in other endocrine glands. The hypothalamus is the "real power behind the throne".
◦ Adrenal Glands: In times of stress, the hypothalamus sends signals via the ANS and pituitary gland to the adrenal glands, which then secrete hormones that prepare the body for exertion (part of the fight-or-flight response).
◦ Oxytocin: A hormone released by the pituitary gland that regulates reproductive behaviors (triggers contractions during birth, stimulates milk release). Newer research suggests far-reaching effects on complex social behavior: fostering adult-adult pair bonding, promoting relationship fidelity in men, fostering feelings of openness and warmth, enhancing fathers' engagement with infants, increasing empathy for suffering, fostering more accurate recognition of others' emotions, and fostering trust in humans. However, overall efforts to replicate findings on oxytocin and trust have yielded inconsistent results. Some theorists suggest oxytocin increases attention and sensitivity to social cues rather than directly promoting prosocial behavior.
• Genes: Know basics of different kinds of studies to assess genetic influence
◦ Chromosomes: Threadlike strands of DNA (deoxyribonucleic acid) molecules that carry genetic information. Humans have 46 chromosomes (23 pairs), with one of each pair from each parent.
◦ Genes: DNA segments that serve as the key functional units in hereditary transmission. Operate in pairs, one from each parent.
◦ Polygenic Traits: Characteristics that are influenced by more than one pair of genes. Most human characteristics (e.g., skin color, motor coordination, most psychological characteristics) are polygenic.
◦ Studies to Assess Genetic Influence:
▪ Family Studies:
• Method: Researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait. If heredity influences a trait, similarity should increase with genetic relatedness (e.g., siblings more similar than cousins).
• Findings (Example): Schizophrenic disorders run in families; first-degree relatives of patients have a nine times higher risk than normal, and this risk decreases with less genetic relatedness.
• Limitation: Family members share both genes and similar environments, which are confounding variables. Thus, family studies offer insights but not definitive evidence of genetic influence.
▪ Twin Studies:
• Method: Researchers assess hereditary influence by comparing the resemblance of identical twins and fraternal twins with respect to a trait.
• Logic: Identical (monozygotic) twins result from one fertilized egg splitting, sharing 100% of their genes. Fraternal (dizygotic) twins result from two separate eggs, sharing, on average, 50% of their genes (like other siblings). Both types usually grow up in similarly shared environments. If identical twins show more similarity on a trait than fraternal twins, it suggests hereditary influence.
• Findings: Identical twins are more similar than fraternal twins on measures of general intelligence and specific personality traits (e.g., extraversion), supporting genetic influence.
▪ Adoption Studies:
• Method: Assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents.
• Logic: Resemblance to biological parents (unshared environment) suggests genetic influence. Resemblance to adoptive parents (unshared genes) suggests environmental influence.
• Findings (Example): Research shows modest similarity (average correlation of .24) between adopted children and both their biological and adoptive parents regarding intelligence, suggesting influence from both heredity and environment.
▪ Genetic Mapping:
• Definition: The process of determining the location and chemical sequence of specific genes on specific chromosomes.
• Human Genome Project: Completed a precise genetic map for humans in 2003, leading to breakthroughs in identifying genes for dichotomous medical traits (e.g., cystic fibrosis).
• Challenges for Behavioral Traits: Progress for behavioral traits (e.g., intelligence, extraversion, musical ability) has been slower because they are typically polygenic (influenced by many genes) and involve continuous variation rather than dichotomies. Individual genes often exert extremely tiny effects.
• Genome-Wide Association Studies: A new approach that examines the entire genome of huge samples to find correlations between genetic markers and behavioral traits, yielding more replicable findings, though specific gene effects remain small.
• Interplay of Heredity and Environment: For behavioral traits, heredity and experience jointly influence most aspects of behavior, and their effects are interactive. Genes confer "dispositions, not destinies". For example, schizophrenia involves inherited vulnerability interacting with life experiences.
• Epigenetics: An emerging field studying heritable changes in gene expression that do not involve modifications to the DNA sequence. Environmental events (e.g., poor nurturance, stress, diet) can chemically "dampen or silence" gene expression, altering traits and behavior, and these epigenetic marks can be passed to subsequent generations. This demonstrates the intertwined nature of genetic and environmental factors.
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Chapter 5: Variations in Consciousness
• Consciousness
◦ Definition: Personal awareness; the awareness of internal and external stimuli. This includes awareness of external events, internal sensations, one's self as a unique being, and one's thoughts about these experiences.
◦ Fluctuating Nature: Consciousness is continually changing, moving, flowing, fluctuating, and wandering ("stream of consciousness," coined by William James). Mind wandering is common but can also foster creativity and problem solving, though it can impair learning.
◦ Levels of Awareness: Sigmund Freud recognized that consciousness is not an all-or-none phenomenon, arguing that feelings and behavior are influenced by unconscious needs, wishes, and conflicts that lie below conscious awareness. Research shows people maintain some awareness during sleep and even under anesthesia (e.g., hearing comments during surgery, selective sensitivity to sounds while asleep).
• EEG (Electroencephalograph)
◦ Definition: A device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the scalp.
◦ Function: Summarizes the rhythm of cortical activity in the brain in terms of line tracings called brain waves. Brain waves vary in amplitude (height) and frequency (cycles per second, cps).
◦ Brain Wave Bands:
▪ Beta (β): 13–24 cps; associated with normal waking thought, alert problem solving.
▪ Alpha (α): 8–12 cps; associated with deep relaxation, blank mind, meditation.
▪ Theta (θ): 4–7 cps; associated with light sleep (e.g., Stage 1 onset).
▪ Delta (Δ): Under 4 cps; associated with deep sleep (slow-wave sleep, Stage 3).
◦ Correlation with Consciousness: Different EEG patterns are associated with different states of consciousness, but the relationship is a correlation; it's unclear if changes in brain activity cause changes in consciousness or vice versa, or if a third factor (e.g., subcortical signals) causes both.
• Biological Rhythms, Circadian
◦ Biological Rhythms: Periodic fluctuations in physiological functioning found in humans and many other animals, indicating internal "biological clocks".
◦ Circadian Rhythms: 24-hour biological cycles found in humans and many other species, particularly influential in the regulation of sleep. Also produce rhythmic variations in blood pressure, urine production, hormonal secretions, and affect alertness and cognitive performance.
◦ Relationship to Sleep: People generally fall asleep as their body temperature drops and awaken as it ascends, suggesting circadian rhythms physiologically prime individuals to fall asleep most easily at a particular time of day.
◦ Mechanism: Light exposure sends inputs from retinal receptors to the suprachiasmatic nucleus (SCN) in the hypothalamus. The SCN sends signals to the pineal gland, which secretes the hormone melatonin. The SCN is the master pacemaker, synchronizing multiple circadian clocks throughout the brain and body.
◦ Disruption: Ignoring circadian rhythms (e.g., due to jet lag or rotating shift work) can lead to poor sleep quality, fatigue, sluggishness, irritability, depression, reduced productivity, impaired social relations, mental health problems, and increased risk for physical diseases and mortality. Jet lag is worse when flying eastward (shortening the day) than westward (lengthening the day). Social jet lag (mismatch between workday and off-day sleep times) can be a chronic problem linked to obesity and cardiovascular symptoms.
• Melatonin
◦ Function: A hormone secreted by the pineal gland that plays a key role in adjusting biological clocks and regulating human circadian rhythms.
◦ Use for Jet Lag: Small doses of melatonin can help travelers resynchronize their biological clocks and reduce jet lag effects, but results are inconsistent, and timing is crucial. It can also help people fall asleep, potentially without the issues of sleeping pills.
• EMG, EOG, EKG
◦ These are physiological recording devices used in sleep laboratories.
◦ EMG (Electromyograph): Records muscular activity and tension.
◦ EOG (Electrooculograph): Records eye movements. Crucial for identifying REM sleep.
◦ EKG (Electrocardiograph): Records the contractions of the heart (heart rate).
• Stages of sleep
◦ Onset: Gradual transition from wakefulness. Predominant EEG activity shifts from alpha waves to theta waves. Average time to fall asleep is about 25 minutes.
◦ Stage 1: A brief transitional stage of light sleep, typically lasting 10–12 minutes.
◦ Stage 2: Consists of light sleep, lasting about 10–25 minutes. Respiration rate, heart rate, muscle tension, and body temperature continue to decline.
◦ Stage 3 (Slow-Wave Sleep, N3): A deep form of sleep where brain waves become higher in amplitude and slower in frequency, with delta waves becoming prominent. Reached in less than an hour and lasts roughly 20–40 minutes.
◦ Overall Cycle: People usually cycle through these stages about four times a night. As the night progresses, REM periods get progressively longer (peaking at 40-60 minutes), and non-REM intervals get shorter. Most slow-wave sleep (N3) occurs early in the night, while REM sleep dominates the second half. A typical young adult's sleep averages about 6% in N1, 48% in N2, 20% in N3 (slow-wave), and 22% in REM. Sleep patterns vary individually and change with age.
• REM vs. Non-REM
◦ REM (Rapid Eye Movement) Sleep:
▪ Characteristics: Fourth stage of sleep, prominent rapid eye movements. Tends to be a "deep" stage (hard to awaken from). Marked by irregular breathing and pulse rate. Muscle tone is extremely relaxed, with the sleeper virtually paralyzed. EEG activity is dominated by high-frequency beta waves, resembling alert/awake patterns (a paradox). Most frequent, vivid, memorable, emotional, dramatic, and rich dreaming occurs in REM sleep.
▪ Discovery: Accidentally discovered in the 1950s by Kleitman and Aserinsky.
▪ Prevalence: Accounts for about 22% of total sleep in young adults, but much more in infants (50% in first few months, declining to 20% by adolescence).
▪ Evolution: Nearly all mammals and birds exhibit REM sleep, with dolphins and some whales being exceptions.
◦ Non-REM Sleep (NREM):
▪ Characteristics: Consists of sleep stages 1 through 3. Marked by an absence of rapid eye movements, modest amounts of dreaming, and varied EEG activity (theta in N1/N2, delta in N3).
▪ Naming: Often referred to as N1, N2, and N3.
• REM Rebound
◦ Definition: When participants in REM-deprivation experiments are finally allowed to sleep without interruption, they experience a "rebound effect," spending extra time in REM periods for one to three nights to make up for their deprivation.
◦ Implication: This indicates that people have a specific and rather strong need for REM sleep.
• Sleep deprivation
◦ Partial Sleep Deprivation (Sleep Restriction): Occurs when people consistently get substantially less sleep than normal.
▪ Prevalence: Many sleep experts believe much of American society experiences chronic sleep deprivation, a global problem.
▪ Negative Effects: Impairs attention, reaction time, motor coordination, and decision making. Negative effects on endocrine and immune system functioning. Decrements in alertness, sustained attention, memory, mood, and problem solving. Triggers hormonal changes that increase hunger and eating, leading to an extra 385 calories/day. Increases susceptibility to palatable, high-calorie foods and undermines self-control.
▪ Accidents: Blamed for a large proportion of transportation and workplace accidents; drowsy driving dramatically increases accident risk (contributing to ~20% of motor vehicle accidents). Sleep-deprived individuals are poor at predicting when they will fall asleep.
▪ Memory/Learning: Sleep seems to enhance memory consolidation for learning that takes place during the day. REM and slow-wave sleep specifically contribute to firming up learning and memory. Adequate sleep (especially REM) is crucial for learning and problem solving; students who sleep less tend to get lower grades, and sacrificing sleep for study can backfire.
▪ Health Consequences: Linked to increased obesity, a risk factor for various health problems. Leads to impaired immune system functioning and increased inflammatory responses, heightening vulnerability to diseases. Associated with increased risk of diabetes, hypertension, coronary disease, and stroke.
▪ Mortality: People who consistently sleep less than 7 hours and more than 9 hours exhibit an elevated mortality risk, with rates especially high for those sleeping over 10 hours (a U-shaped relationship). Recommended adult sleep duration is 7–9 hours per night.
◦ Selective Deprivation:
▪ Method: Participants awakened whenever they enter REM sleep or slow-wave sleep, getting adequate non-REM sleep but deprived of the specific stage.
▪ Effects: Little impact on daytime functioning, but participants spontaneously shift into the deprived stage more and more frequently, and experience a "rebound effect" (spending extra time in that stage) when allowed to sleep normally. This suggests specific, strong needs for REM and slow-wave sleep.
• Sleep disorders (insomnia, narcolepsy, sleep apnea, somnambulism, REM sleep behavior disorder)
◦ Insomnia:
▪ Definition: Chronic problems in getting adequate sleep that result in daytime fatigue and impaired functioning.
▪ Patterns: (1) difficulty falling asleep initially, (2) difficulty remaining asleep, (3) persistent early-morning awakening.
▪ Consequences: Reduced productivity, increased absenteeism, elevated risk for accidents, anxiety, depression, and a variety of serious health problems (e.g., cardiovascular disease, diabetes, hypertension).
▪ Prevalence: About 10% of adults endure chronic insomnia, another 20-30% have intermittent symptoms. Increases with age, more common in women.
▪ Treatment: Many depend on questionable over-the-counter aids. Medical treatment involves benzodiazepine sedatives (e.g., Dalmane) and newer nonbenzodiazepine sedatives (e.g., Ambien). Sedatives help falling and staying asleep but have problems: overdose risk (especially with alcohol), abuse potential, carryover effects (drowsiness, drowsy driving), reduced effectiveness with continued use (tolerance, escalating dependency), and withdrawal symptoms. Cognitive-behavioral therapy (CBT) is recommended as the first-line treatment. Lifestyle modifications (avoid naps, exercise, minimize stimulants/alcohol, regular bedtime, conducive environment) can also help.
◦ Narcolepsy:
▪ Definition: A disease marked by sudden and irresistible onsets of sleep during normal waking periods, where a person goes directly from wakefulness into REM sleep. Potentially dangerous if it occurs while driving or walking.
▪ Prevalence: Relatively uncommon (about 0.05% of the population).
▪ Cause: Main cause is impairment in the regulation of REM sleep, due to the loss of orexin neurons in the hypothalamus. Some individuals show a genetic predisposition.
▪ Treatment: Stimulant drugs used with modest success, but carry their own problems.
◦ Sleep Apnea:
▪ Definition: Involves frequent, reflexive gasping for air that awakens a person and disrupts sleep. A person literally stops breathing for a minimum of 10 seconds. Usually accompanied by loud snoring.
▪ Prevalence: Seen in about 6%–7% of adults, increasing.
▪ Higher Incidence: Males, older adults, postmenopausal women, obese people, and those with a genetic predisposition.
▪ Consequences: Disruptive sleep, excessive daytime sleepiness. More serious than often appreciated: increases vulnerability to cardiovascular diseases, more than doubles overall mortality risk. Associated with declines in attention, memory, and cognitive functioning.
▪ Treatment: Lifestyle modifications (weight loss, reduced alcohol, improved sleep hygiene), drug therapy, special masks/oral devices, and surgery.
◦ Somnambulism (Sleepwalking):
▪ Definition: Occurs when a person arises and wanders about while remaining asleep.
▪ Prevalence: About 15% of children exhibit it. 3.6% of adults reported an episode in the last year.
▪ Timing: Tends to occur during the first 3 hours of sleep, specifically during slow-wave sleep (N3).
▪ Characteristics: Episodes last from 1-2 minutes up to 30 minutes. Sleepwalkers may awaken during their journey or return to bed with no recollection.
▪ Causes: Unknown, but appears to have a genetic predisposition, and episodes are associated with prior sleep deprivation and increased stress.
▪ Risks: Accidents and injuries are common, including life-threatening incidents.
▪ Myth: Sleepwalkers are not acting out their dreams (dreams occur mostly in REM, while sleepwalking is in non-REM). It is generally best to gently awaken a sleepwalker to prevent injury.
◦ REM Sleep Behavior Disorder (RBD):
▪ Definition: Marked by potentially troublesome dream enactments during REM periods.
▪ Symptoms: Individuals may talk, yell, gesture, flail, or leap out of bed, often reporting being chased or attacked in their dreams. Enactments can be violent, causing injury to self or bed partners.
▪ Demographics: Occurs mostly in men, typically beginning in their 50s or 60s.
▪ Cause: Appears to be deterioration in brainstem structures that are normally responsible for immobilizing the body during REM sleep (preventing dream enactments).
▪ Link to Parkinson's: A majority of people diagnosed with RBD eventually develop neurodegenerative disorders, especially Parkinson’s disease, with RBD symptoms sometimes preceding Parkinson's by as much as 10 years.